Supermarket shopping becomes an essential consumer behavior of the modern society. Supermarket shopping carts, as convenient means of delivery, play an important role. After the shoppers finished using the shopping carts, the employees of the supermarkets return the carts to the original places. This consumes many human resources and increases the labor costs. Shopping carts may also be stolen. Shopping carts are expensive, losing them costs dearly to the supermarkets.
To secure shopping carts and to reduce labor costs, anti-stealing shopping carts have been developed. The basic principle is that a wheel of the shopping cart can be automatically locked through the supermarket's security settings so that the shopping cart cannot be pushed away.
Sudden locking of the shopping cart through the security settings may damage the wheel of the shopping cart. Furthermore, sudden locking of the shopping carts may present danger to the users who are using them. Therefore, new shopping carts, which are both stealing-proof and safe to the users, are needed.